Device for lowering persons and loads

ABSTRACT

The present invention concerns a device for lowering persons and loads comprising, rotatably journaled in a suitable device body, a rope drum from which a rope is discharged, to which the load to be lowered is fastened, and the rotation of which is hydraulically braked.

United States Patent Inventor .Ialmui Selim Vlrkki Tuulitie 5, Vantaa, Finland Appl. No. 801.998

Filed Feb. 25, 1969 Patented July 27, 1971 Priority Feb. 27, 1968: Dec. 16,1968

Finland 510/68; 3602/68 DEVICE ron LOWERING reasons AND LOADS 1 Claim, 4 Drawing Figs.

US. Cl 254/160,

254/ 158 Int. Cl. A62b 1/12 FieldolSearch 254/158,

References Cited UNITED STATES PATENTS Gray et a1. Young Appelman Wright et a1. Tessin Sherbrook et a1.

Primary Examiner-Evon C. Blunk Assistant Examiner-Alfred N. Goodman Attorney-Richards & Geier ABSTRACT: The present invention concerns a device for lowering persons and loads comprising, rotatably journaled in a suitable device body, a rope drum from which a rope .is discharged, to which the load to be lowered is fastened, and the rotation of which is hydraulically braked.

WHENTEDv JUL 2 1 Ian SHEEI 1 0F 3 FIGJ INVENTOR: J. S, VOW/ 1: 6B

PATENTEDJULNISII 3,595,528

SHEET 2 [IF 3 H63 INVENTOR:

J. 5. VL'rK/al ATTOLNBSS PATENIEB JUL2'! ran SHEET 3 BF 3 FIGA I NVENTOR: ].S. Vim/a ATTOKNEUS DEVICE FOR LOWERING PERSONS AND LOADS The present invention concerns a device for lowering persons and loads comprising, rotatably journaled in a suitable device body, a rope drum from which a rope is discharged, to which the load to be lowered is fastened, and the rotation of which is braked. A device according to the invention is fit to be used in a great multitude of applications. For instance, it may be used as a safety device for building workers, in which case the worker may attach his safety belt to the device. If for some reason the worker falls, the device according to the invention will lower him to the ground with comparatively small, constant velocity. Likewise, the device may be used as a piece of standard equipment mounted on the walls of buildings and enabling the people in the house e.g. in impending danger of fire to escape through the window and to be lowered safely to the ground. The device is also appropriate for the lowering of all kinds of loads, in which instance it is also possible to lift lighter loads, although this is in no way necessary in view of the operation of the device.

Devices of similar kind are previously known in which the rotation of the rope drum is mechanically braked by means of a mechanism based on centrifugal force and driven by the rope drum, or by means of a hydraulic pump which the rope drum has been arranged to drive. The previously known devices have been comparatively complex of their construction, for which reason their initial cost has been so high that their use has not gained any general spread. Owing to structural reasons, they have also been very heavy and they have therefore not been usable as safety equipment for roof workers, because they have interfered too strongly with the work.

The aim of the present invention is accordingly to afford a new type of highly reliable, structurally simple, small-sized and light safety device which may be used in various emergencies and, also in general, in the way of a lift device for lowering various loads. Since the safety device will have to operate in exceedingly rare instances, and preferably should not need to operate ever, particular attention has been paid to the feature that such design of the device might be achieved that it would not need any maintenance and that it should be positively ready to operate even after years of inaction.

A device according to the invention is therefore mainly characterized in that the rope drum has been arranged to drive by means of a screw transmission a piston coacting with a suitable brake cylinder, this drive causing the piston to move in the direction of the longitudinal axis of the cylinder, and that this cylinder is closed and filled with a pressure medium, and that the flow of the pressure medium from one side of the piston to its other side when the device operates and the piston moves in the cylinder is comparatively strongly restricted or throttled.

It is advantageous in practice in this connection if for location of the said brake cylinder the interior of the rope drum is used, whereby the device can be made very small in size. Then, too, the brake cylinder may either be placed within the drum as a separate unit, or a design solution may be applied in which the inner surface of the rope drum circumscribes and forms the brake cylinder. The screw transmission displacing the piston within the rope drum, which is operated by the rotatory motion of the drum and displaces the piston in axial direction inside the brake cylinder, can be accomplished by numerous different designs. Similarly, the slow and comparatively strongly restricted, controlled flow of pressure medium from one side to the other of the piston, which is essential in view of operation of the device, can also be accomplished by rather a great number of different designs. It is perhaps simplest of all to employ sufficiently wide tolerances between the piston and the structural parts associated with it. Another, rather simple solution is to provide the piston with one or several small-diameter holes or valves acting in the manner of a throttling valve.

The invention is described in closer detail in the following, with reference to the attached schematic drawing and to some embodiments of the invention shown in this drawing.

FIG. 1 shows a device according to the invention, in section, and FIG. 2 shows the same device in axonometric presentation and mounted on the wall of a building. This device is appropriate to be used e.g. as a piece of safety equipment in respect of fire hazard, in which case it is most appropriately mounted above the window openings.

FIG. 3 shows another model, in sectional view. This model is especially intended to be used as a safety device for building workers and other persons working at great height, and which is attached to be connected with the safety belt of such workers.

FIG. 4 shows in section and in axonometric projection another modification of the model consistentwith FIGS. 1 and 2.

In the embodiment according to FIGS. 1 and 2, the device according to the invention comprises end'flanges 9 acting as device body, these flanges being attachable by means of brackets 6 e.g. to a wall or some other appropriate base. Integrally connected with the end flanges 9 by means of the nuts 8 is a shaft 4, the thickest part of which has square cross section, as has been indicated in FIG. 1. A rope drum 1 provided with flanges, which has a hollow interior constituting the brake cylinder space 2, has been rotatably journaled on the shaft 4 by means of the end plates 11 serving as closing plugs. The space operating as brake cylinder is completely closed and filled with some appropriate hydraulic fluid. The wall of the brake cylinder 2 has been provided with a thread 2a, which drives the piston 5 fitted movably on the shaft 4, and which piston has on its outer circumference a thread engaging with the said thread 20. The rope drum 1 has been divided with an intermediate flange 3 into two parts, a separate rope being wound on either half in opposite directions so that when the rope 13a (FIG. 2) moves downward, the rope 13b is drawn into the device and wound upon the drum, and vice versa.

When the device operates and the rope drum rotates, the piston 5 will move to the left or to the right, depending on the direction of rotation of the drum in each particular instance. The piston has an opening 12 through which hydraulic fluid can be forced to the opposite side of the piston. Owing to the cross-sectional shape of the shaft 4, the piston 5 cannot rotate; instead, it is displaced purely axially under the driving action of the screw engagement between it and the brake cylinder surface 2a. I

The device is covered by a protective cover 10, which at the same time prevents tangling of the rope and acts as weather protection. For mounting on the base, the mounting brackets 6 of the device have holes 7 through which it can be attached e.g. with the aid of bolts 14.

In FIG. 3 a device has been shown which is intended to be attached by the ring 15 fixed to the body 14 of the device, to the workers safety belt or other equipment. The end of the rope l3 emerging from the lower part of the device is intended to be attached e.g. to a smoke stack or ventilation chimney or to a special receptacle permanently fixed to the building. This device is particularly suitable for use in connection with all kinds of work on the roofs of buildings.

The device comprises a rope drum 1, which together with the part 1a acting as brake cylinder consists of one single casting. The cylinder space 2 has been closed at its ends by closing plates 1 I so that it cannot be opened with common tools. The device further comprises a shaft 4, which has been unturnably attached to the device body 14. The shaft 4 has been provided with a thread 4a, which has it coacting thread on the piston 5, this piston being free to move axially from right to left. In order that at rotation of the rope drum 1 and of the associated parts la and 11 the piston 5 might rotate along with them and be displaced axially along its screw engagement, a guide 17 has been mounted in the cylinder space between the end plates 11. In this model thus, differing from the above, the piston simultaneously rotates while it moves from right to left. For the hydraulic fluid flow an opening 12 has been made in the piston similarly as in the device represented by FIGS. 1 and 2. Furthermore, in the shaft 4 a bore 22 has been made, which connects by openings 21 with the cylinder space 2. In

the bore a nozzle needle 20 has been mounted, choice of the size of this needle enabling the amount of fluid to be regulated which can pass through this system.

Moreover, the device comprises a flat spiral spring 19, one end of this spiral being attached to the outer surface of the part acting as power cylinder and the other end, to a pro jection 18 fixed to the device body. While the worker is at work, the rope 13 automatically remains taut all the time because the flat spring 19 all the time draws in rope as the worker approaches the point where the rope 13 has been attached. For the same reason, when the worker moves comparatively slowly in the course of his work, the piston may move comparatively easily in the range of the shaft 4 between both openings 21. For rooftop workers, for instance, it is advantageous to place the openings 21 so that rope in the length of 6 to 9 meters may be comparatively easily unwound from the drum. If theworker begins to fall, the piston will move past the left opening 21, whereafter the hydraulic fluid can pass over to the other wide of the piston only through the opening 12, and the rate of fall of the worker is automatically slowed down e.g. to be 2 meters per second. It is also possible to arrange for use in connection with the nozzle assembly 21,22 of some valve design previously known in itself and employed in hydraulic circuits, which only admits a given maximum volume flow to pass through, whereby e.g. in the event of the worker's slipping the device immediately begins to brake his fall powerfully, even though it does not interfere in any way with his usual comparatively slow movements in the course of his work. It is not absolutely necessary for the device to lower the worker all the way to the ground, the main thing being that he will remain suspended from the rope 13 without being subjected to any abrupt jerk. However, it is advantageous to design the device so that the flat spring 19 will come loose or break at a given stage, and in which instance enough rope is placed on the rope drum so that the worker will be lowered all the way to the ground. Once the device has operated to the full extent of its action, it has to be placed into operating condition once more at a special servicing plant; this for the reason that it is indicated to make the body 14 completely closed except for the small aperture 16 for the rope 13, so that the device can at no stage be intentionally or unintentionally manipulated by unauthorized persons in any manner detracting from its reliability of operation.

In FIG. 4 one further embodiment of the device has been shown. The principle of operation of this device is the same as that of the device represented by FIGS. 1 and 2, from which it differs in the first place in respect of some design solutions that have been employed.

This device comprises a body 23 and, journaled on a pin 25 attached to this body, a coupling member 24, which rotates along with the rope drum 1. Within the rope drum a separate brake cylinder 1b has been placed, with closing plates 11 at its ends. The bolts 17 acting as guides for the piston bind the closing plates 11 and the cylinder lb positively to the body 23 of the device so that the cylinder 1b and piston 5 cannot follow the rotation of the rope drum 1. In the end pieces 11 acting as closing plates, the shaft 4 is carried, which has been provided with a thread for imparting motion to the piston 5. This shaft 4 is positively connected with the coupling member 24 and consequently rotates along with the rope drum. When the rope drum rotates, the shaft 4 actuates the piston 5 so that the latter moves axially in either direction along the guides 17, which at the same time prevent the piston from rotating. In this design example no flow passages have been provided, instead of which the parts have been fitted together with such a degree of leakage that the fluid may pass from one side of the piston to the other through the gaps provided by the tolerances. In this model, too, the rope drum 3 has been provided with an intermediate flange 3 so that the device may be continuously used for lowering loads, in connection with which it is also possible at the same time to hoist up loads which are lighter than the load that is being lowered. This device is also applicable for a ye great variety of uses although it was originally designed, in t e first place, to serve as a safety device in view 0 fire hazard and to be mounted e.g. above a window on the house facade.

Within the scope of the invention, the brake cylinder may also be placed at some point other than inside the rope drum, but there is usually no cause to do so. Likewise, the transfer of pressure medium from one side of the piston to the other may be accomplished and governed by a number of different solutions e.g. with the aid of separate pipes. By suitable adjustment of the tolerances, for instance, the device can be made such that the descent of the load is at first slowly accelerated and, later prior to ground contact, a slowly decelerated motion, whereby the total drop time will be less and the transporting capacity of the device e.g. in conflagrations is higher.

In the drawing the tightenings between the different parts have not been more closely shown, and these details may be solved in numerous different ways. In practice, it is important in every case that the brake cylinder is completely tight so that no pressure medium can leak from it when the device operates.

If the device is used as a lift, it is advantageous to design it so that the flow apertures for the pressure medium can be made larger or smaller by means of an appropriate valve device, according to the conditions and requirements imposed by the weight of the particular load that is to be lowered. It is most advantageous in practice to use in the brake cylinder some oil possessing a good viscosity index and the viscosity of which is at least not greatly dependent, within the range of temperatures which occur, of ambient temperature. The device may obviously also be designed to operate pneumatically, but this is not usually indicated in practice because the requisite tolerances increase the initial cost of the device.

Even otherwise the invention is not narrowly confined to anything that has been presented in the drawing or said in the foregoing, in that the inventive idea may also be realized by means of many other structural solutions.

I claim:

1. A device for lowering persons and loads, comprising two parallel flanges having brackets for attachment to a wall, a shaft extenbing between said flanges, nuts'carried by the ends of said shaft and firmly connecting said shaft to said flanges, a portion of said shaft between said flanges being square in cross section, a rope drum surrounding said shaft, end plates fixed to opposite ends of said drum and rotatably mounted on round opposed ends of said shaft, said drum having inner screw threads, a piston slidably mounted upon the square portion of said shaft and having outer screw threads meshing with said inner screw threads, said piston having an opening formed therein for the passage of hydraulic fluid adapted to fill the space enclosed by said drum, the portions of said shaft separated by said piston being adapted to carry oppositely wound rope ends. 

1. A device for lowering persons and loads, comprising two parallel flanges having brackets for attachment to a wall, a shaft extending between said flanges, nuts carried by the ends of said shaft and firmly connecting said shaft to said flanges, a portion of said shaft between said flanges being square in cross section, a rope drum surrounding said shaft, end plates fixed to opposite ends of said drum and rotatably mounted on round opposed ends of said shaft, said drum having inner screw threads, a piston slidably mounted upon the square portion of said shaft and having outer screw threads meshing with said inner screw threads, said piston having an opening formed therein for the passage of hydraulic fluid adapted to fill the space enclosed by said drum, the portions of said shaft separated by said piston being adapted to carry oppositely wound rope ends. 